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1.
Trauma Surg Acute Care Open ; 9(1): e001291, 2024.
Article in English | MEDLINE | ID: mdl-38318345

ABSTRACT

Introduction: The analysis of surgical research using bibliometric measures has become increasingly prevalent. Absolute citation counts (CC) or indices are commonly used markers of research quality but may not adequately capture the most impactful research. A novel scoring system, the disruptive score (DS) has been found to identity academic work that either changes paradigms (disruptive (DIS) work) or entrenches ideas (developmental (DEV) work). We sought to analyze the most DIS and DEV versus most cited research in civilian trauma. Methods: The top papers by DS and by CC from trauma and surgery journals were identified via a professional literature search. The identified publications were then linked to the National Institutes of Health iCite tool to quantify total CC and related metrics. The top 100 DIS and DEV publications by DS were analyzed based on the area of focus, citation, and perceived clinical impact, and compared with the top 100 papers by CC. Results: 32 293 articles published between 1954 and 2014 were identified. The most common publication location of selected articles was published in Journal of Trauma (31%). Retrospective reviews (73%) were common in DIS (73%) and top CC (67%) papers, while DEV papers were frequently case reports (49%). Only 1 publication was identified in the top 100 DIS and top 100 CC lists. There was no significant correlation between CC and DS among the top 100 DIS papers (r=0.02; p=0.85), and only a weak correlation between CC and DS score (r=0.21; p<0.05) among the top 100 DEV papers. Conclusion: The disruption score identifies a unique subset of trauma academia. The most DIS trauma literature is highly distinct and has little overlap with top trauma publications identified by standard CC metrics, with no significant correlation between the CC and DS. Level of evidence: Level IV.

2.
J Trauma Acute Care Surg ; 95(2S Suppl 1): S157-S169, 2023 08 01.
Article in English | MEDLINE | ID: mdl-37184517

ABSTRACT

BACKGROUND: Bibliometric analysis of surgical research has become increasingly prevalent. Citation count (CC) is a commonly used marker of research quality, but may overlook impactful military research. The disruption score (DS) evaluates manuscripts on a spectrum from most innovative with more positive scores (disruptive [DR]) to most entrenched with more negative scores (developmental; DV). We sought to analyze the most DR and DV versus most cited research in military trauma. METHODS: Top trauma articles by DS and by CC were identified via professional literature search. All publications in military journals were included. Military trauma-related keywords were used to query additional top surgical journals for military-focused publications. Publications were linked to the iCite NIH tool for CC and related metrics. The top 100 DR and DV publications by DS were analyzed and compared with the top 100 articles by CC. RESULTS: Overall, 32,040 articles published between 1954 and 2014 were identified. The average DS and CC were 0.01 and 22, respectively. Most articles were published in Mil Med ( 68%). The top 100 DR articles were frequently published in Mil Med (51%) with a mean DS of 0.148. Of these, the most cited article was only the 40th most disruptive. The top 100 CC articles averaged a DS of 0.009 and were commonly found in J Trauma (53%). Only five publications were on both the top 100 DR and top 100 CC lists; 19 were on both the top DV and CC lists. Citation count was not correlated with DR ( r = -0.134; p = 0.07) and only weakly correlated with DV ( r = 0.215; p = 0.003). CONCLUSION: DS identifies publications that changed military paradigms and future research directions previously overlooked by citation count alone. The DR and DV articles are distinct with little overlap between highly cited military articles. Multiple bibliometric measures should be employed to avoid overlooking impactful military trauma research. LEVEL OF EVIDENCE: Diagnostic Test or Criteria; Level IV.


Subject(s)
Journal Impact Factor , Military Personnel , Humans , Bibliometrics , Publications
3.
J Transl Med ; 21(1): 247, 2023 04 07.
Article in English | MEDLINE | ID: mdl-37029410

ABSTRACT

BACKGROUND: The clinical heterogeneity of SLE with its complex pathogenesis remains challenging as we strive to provide optimal management. The contribution of platelets to endovascular homeostasis, inflammation and immune regulation highlights their potential importance in SLE. Prior work from our group showed that the Fcγ receptor type IIa (FcγRIIa)-R/H131 biallelic polymorphism is associated with increased platelet activity and cardiovascular risk in SLE. The study was initiated to investigate the platelet transcriptome in patients with SLE and evaluate its association across FcγRIIa genotypes and distinct clinical features. METHODS: Fifty-one patients fulfilling established criteria for SLE (mean age = 41.1 ± 12.3, 100% female, 45% Hispanic, 24% black, 22% Asian, 51% white, mean SLEDAI = 4.4 ± 4.2 at baseline) were enrolled and compared with 18 demographically matched control samples. The FCGR2a receptor was genotyped for each sample, and RNA-seq was performed on isolated, leukocyte-depleted platelets. Transcriptomic data were used to create a modular landscape to explore the differences between SLE patients and controls and various clinical parameters in the context of FCGR2a genotypes. RESULTS: There were 2290 differentially expressed genes enriched for pathways involved in interferon signaling, immune activation, and coagulation when comparing SLE samples vs controls. When analyzing patients with proteinuria, modules associated with oxidative phosphorylation and platelet activity were unexpectedly decreased. Furthermore, genes that were increased in SLE and in patients with proteinuria were enriched for immune effector processes, while genes increased in SLE but decreased in proteinuria were enriched for coagulation and cell adhesion. A low-binding FCG2Ra allele (R131) was associated with decreases in FCR activation, which further correlated with increases in platelet and immune activation pathways. Finally, we were able to create a transcriptomic signature of clinically active disease that performed significantly well in discerning SLE patients with active clinical disease form those with inactive clinical disease. CONCLUSIONS: In aggregate, these data demonstrate the platelet transcriptome provides insight into lupus pathogenesis and disease activity, and shows potential use as means of assessing this complex disease using a liquid biopsy.


Subject(s)
Lupus Erythematosus, Systemic , Lupus Nephritis , Female , Male , Humans , Transcriptome/genetics , Receptors, IgG/genetics , Blood Platelets , Lupus Erythematosus, Systemic/genetics , Genotype , Phenotype , Lupus Nephritis/genetics
4.
Toxicol Lett ; 379: 48-55, 2023 Apr 15.
Article in English | MEDLINE | ID: mdl-36958672

ABSTRACT

Diethylene glycol (DEG) mass poisonings have resulted from ingestion of adulterated pharmaceuticals, leading to proximal tubular necrosis and acute kidney injury. Diglycolic acid (DGA), one of the primary metabolites, accumulates greatly in kidney tissue and its direct administration results in toxicity identical to that in DEG-treated rats. DGA is a dicarboxylic acid, similar in structure to Krebs cycle intermediates such as succinate. Previous studies have shown that DGA is taken into kidney cells via the succinate-related dicarboxylate transporters. These studies have assessed whether the DGA that is taken up by primary cultures of human proximal tubule (HPT) cells is effluxed. In addition, a possible mechanism for efflux, via organic anion transporters (OATs) that exchange external organic anions for dicarboxylates inside the cell, was assessed using transformed cell lines that actively express OAT activities. When HPT cells were cultured on membrane inserts, then loaded with DGA and treated with the OAT4/5 substrate estrone sulfate or the OAT1/3 substrate para-aminohippurate, no DGA efflux was seen. A repeat of this experiment utilizing RPTEC/TERT1 cells with overexpressed OAT1 and OAT3 had similar results. In these cells, but not in HPT cells, co-incubation with succinate increased the uptake of PAH, confirming the presence of OAT activity in the RPTEC/TERT1 cells. Thus, despite OATs stimulation in cells with OAT activity, there was little to no efflux of DGA from the cells. This study concluded that DGA is poorly transported out of cells and that stimulation of OAT transporters is not a viable target for reducing DGA accumulation in cells.


Subject(s)
Glycolates , Kidney Tubules, Proximal , Rats , Humans , Animals , Kidney Tubules, Proximal/metabolism , Glycolates/toxicity , Glycolates/metabolism , Succinates/metabolism , Succinic Acid/metabolism , Organic Anion Transporters, Sodium-Independent/genetics , Organic Anion Transporters, Sodium-Independent/metabolism
5.
Curr Opin Anaesthesiol ; 36(2): 137-146, 2023 Apr 01.
Article in English | MEDLINE | ID: mdl-36607823

ABSTRACT

PURPOSE OF REVIEW: This article reviews the impact and importance of delirium on patients admitted to the ICU after trauma, including the latest work on prevention and treatment of this condition. As the population ages, the incidence of geriatric trauma will continue to increase with a concomitant rise in the patient and healthcare costs of delirium in this population. RECENT FINDINGS: Recent studies have further defined the risk factors for delirium in the trauma ICU patient population, as well as better demonstrated the poor outcomes associated with the diagnosis of delirium in these patients. Recent trials and meta-analysis offer some new evidence for the use of dexmedetomidine and quetiapine as preferred agents for prevention and treatment of delirium and add music interventions as a promising part of nonpharmacologic bundles. SUMMARY: Trauma patients requiring admission to the ICU are at significant risk of developing delirium, an acute neuropsychiatric disorder associated with increased healthcare costs and worse outcomes including increased mortality. Ideal methods for prevention and treatment of delirium are not well established, especially in this population, but recent research helps to clarify optimal prevention and treatment strategies.


Subject(s)
Delirium , Aged , Humans , Delirium/prevention & control , Hospitalization , Incidence , Intensive Care Units , Risk Factors
7.
Aust Crit Care ; 36(1): 133-137, 2023 01.
Article in English | MEDLINE | ID: mdl-36470778

ABSTRACT

BACKGROUND: Although well-established internationally, nurse practitioners (NPs) in Australian adult intensive care units (ICUs) are rare. Australian literature clearly highlights the importance of creating ICU NP roles to meet emerging demands. An ICU NP model of care at a metropolitan hospital in Sydney provides care in four core practice areas: complex case management, vascular access, tracheostomy management, and intrahospital transport of critically ill patients. The ICU NPs also provide training and assessment for ICU nurses and medical officers in these same core practice areas and can efficiently meet service gaps in crisis such as the most recent COVID-19 pandemic. RESULTS: The ICU NP program described is an innovative model of care that has demonstrated potential benefits to patients and their families. Potential benefits to the healthcare system including supporting advanced practice nursing development in regional and rural Australia and in addressing future ICU workforce issues are also identified. This model of care provides a clear role and structure for the integration of NPs in the adult ICU. Research to evaluate the impact of the role is required and is underway. CONCLUSIONS: This model is being used to develop a national adult ICU NP fellowship training program for ICU transitional NPs preparing for endorsement or endorsed NPs who require additional ICU-specific training. This immersive clinical training program combined with didactic learning modules offers a framework to support the implementation of the adult ICU NP role as well as a framework for NP fellowship programs in other specialties.


Subject(s)
COVID-19 , Nurse Practitioners , Humans , Adult , Australia , Pandemics , Intensive Care Units , Nurse Practitioners/education , Critical Care
8.
Arthritis Rheumatol ; 75(5): 711-722, 2023 05.
Article in English | MEDLINE | ID: mdl-36245285

ABSTRACT

OBJECTIVE: Platelets are mediators of inflammation with immune effector cell properties and have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). This study investigated the role of platelet-associated lectin, galactoside-binding, soluble 3 binding protein (LGALS3BP) as a mediator of inflammation in SLE and as a potential biomarker associated with clinical phenotypes. METHODS: We performed RNA sequencing on platelets from patients with SLE (n = 54) and on platelets from age-, sex-, and race/ethnicity-matched healthy controls (n = 18) and measured LGALS3BP levels in platelet releasate and in circulating serum. We investigated the association between LGALS3BP levels and the prevalence, disease severity, and clinical phenotypes of SLE and studied platelet-mediated effects on myeloid inflammation. RESULTS: Platelets from patients with SLE exhibited increased expression of LGALS3BP (fold change 4.0, adjusted P = 6.02 × 10-11 ). Platelet-released LGALS3BP levels were highly correlated with circulating LGALS3BP (R = 0.69, P < 0.0001), and circulating LGALS3BP levels were correlated with the severity of disease according to the SLE Disease Activity Index (r = 0.32, P = 0.0006). Specifically, circulating LGALS3BP levels were higher in SLE patients with lupus nephritis than in patients with inactive disease (4.0 µg/ml versus 2.3 µg/ml; P < 0.001). Interferon-α induced LGALS3BP transcription and translation in a megakaryoblastic cell line (MEG-01) in a dose-dependent manner. Recombinant LGALS3BP and platelet releasates from SLE patients enhanced proinflammatory cytokine production by macrophages. CONCLUSIONS: Our results support that platelets act as potent effector cells that contribute to the pathogenesis of SLE by secreting proinflammatory LGALS3BP, which also represents a novel biomarker of SLE clinical activity.


Subject(s)
Blood Platelets , Lupus Erythematosus, Systemic , Humans , Blood Platelets/metabolism , Carrier Proteins/metabolism , Inflammation/metabolism , Biomarkers , Antigens, Neoplasm/metabolism , Biomarkers, Tumor
9.
Kidney Int Rep ; 7(10): 2242-2250, 2022 Oct.
Article in English | MEDLINE | ID: mdl-36217517

ABSTRACT

Introduction: Platelet dysfunction and cardiovascular risk are well-recognized features of chronic kidney disease (CKD). Platelets drive the development and progression of cardiovascular disease (CVD). The relationships between kidney function, platelet activity, and cardiovascular risk are poorly defined. Methods: We compared platelet activity and incident cardiovascular events by CKD status (estimated glomerular filtration rate [eGFR] < 60 ml/min per 1.73 m2) using data from the Platelet Activity and Cardiovascular Events study, a prospective cohort study that enrolled adults with peripheral artery disease (PAD) undergoing lower extremity revascularization. Platelet activity was measured using light transmission aggregometry (LTA) in response to submaximal dose agonist stimulation, and the subjects were followed for incident adverse cardiovascular events for a median of 18 months. Results: Overall, 113 of 285 (40%) subjects had CKD. Subjects with, versus without, CKD had higher platelet aggregation in response to stimulation with adenosine diphosphate (ADP), serotonin, epinephrine, and arachidonic acid (AA) + ex vivo aspirin (P < 0.05 for each). Following multivariable adjustment, subjects with CKD had elevated risk for myocardial infarction (MI) (adjusted hazard ratio 2.2, 95% confidence interval [1.02-4.9]) and major adverse cardiovascular events (MACE) (1.9 [1.2-3.3]) compared to those without CKD. Platelet aggregation in response to submaximal dose agonist stimulation mediated 7% to 26% of the excess risk for cardiovascular events associated with CKD. Conclusion: Among subjects with PAD undergoing lower extremity revascularization, CKD is associated with increased platelet activity that mediates, in part, elevated cardiovascular risk.

10.
Toxicol Sci ; 190(1): 1-12, 2022 10 27.
Article in English | MEDLINE | ID: mdl-36087010

ABSTRACT

Diethylene glycol (DEG) mass poisonings have resulted from ingestion of pharmaceuticals mistakenly adulterated with DEG, typically leading to proximal tubular necrosis and acute kidney injury. The metabolite, diglycolic acid (DGA) accumulates greatly in kidney tissue and its direct administration results in toxicity identical to that in DEG-treated rats. DGA is a dicarboxylic acid, similar in structure to metabolites like succinate. These studies have assessed the mechanism for cellular accumulation of DGA, specifically whether DGA is taken into primary cultures of human proximal tubule (HPT) cells via sodium dicarboxylate transporters (NaDC-1 or NaDC-3) like those responsible for succinate uptake. When HPT cells were cultured on membrane inserts, sodium-dependent succinate uptake was observed from both apical and basolateral directions. Pretreatment with the NaDC-1 inhibitor N-(p-amylcinnamoyl)anthranilic acid (ACA) markedly reduced apical uptakes of both succinate and DGA. Basolateral uptake of both succinate and DGA were decreased similarly following combined treatment with ACA and the NaDC-3 inhibitor 2,3-dimethylsuccinate. When the cells were pretreated with siRNA to knockdown NaDC-1 function, apical uptake of succinate and toxicity of apically applied DGA were reduced, while the reduction in basolateral succinate uptake and basolateral DGA toxicity was marginal with NaDC-3 knockdown. DGA reduced apical uptake of succinate but not basolateral uptake. This study confirmed that primary HPT cells retain sodium dicarboxylate transport functionality and that DGA was taken up by these transporters. This study identified NaDC-1 as a likely and NaDC-3 as a possible molecular target to reduce uptake of this toxic metabolite by the kidney.


Subject(s)
Dicarboxylic Acid Transporters , Symporters , Humans , Rats , Animals , Dicarboxylic Acid Transporters/genetics , Dicarboxylic Acid Transporters/metabolism , Kidney Tubules, Proximal/metabolism , Succinates , Succinic Acid/metabolism , Sodium/metabolism , Cell Membrane/metabolism , Organic Anion Transporters, Sodium-Dependent/metabolism , Symporters/metabolism
11.
J Trauma Acute Care Surg ; 93(5): 604-612, 2022 11 01.
Article in English | MEDLINE | ID: mdl-35444156

ABSTRACT

BACKGROUND: Posttraumatic venous thromboembolism (VTE) remains prevalent in severely injured patients despite chemoprophylaxis. Importantly, although platelets are central to thrombosis, they are not routinely targeted in prevention of posttraumatic VTE. Furthermore, platelets from injured patients show ex vivo evidence of increased activation yet impaired aggregation, consistent with functional exhaustion. However, the relationship of this platelet functional phenotype with development of posttraumatic VTE is unknown. We hypothesized that, following injury, impaired ex vivo platelet aggregation (PA) is associated with the development of posttraumatic VTE. METHODS: We performed a secondary analysis of 133 severely injured patients from a prospective observational study investigating coagulation and inflammation (2011-2019). Platelet aggregation in response to stimulation with adenosine diphosphate (ADP), collagen, and thrombin was measured at presentation (preresuscitation) and 24 hours (postresuscitation). Viscoelastic clot strength and lysis were measured in parallel by thromboelastography. Multivariable regression examined relationships between PA at presentation, 24 hours, and the change (δ) in PA between presentation and 24 hours with development of VTE. RESULTS: The 133 patients were severely injured (median Injury Severity Score, 25), and 14% developed VTE (all >48 hours after admission). At presentation, platelet count and PA were not significantly different between those with and without incident VTE. However, at 24 hours, those who subsequently developed VTE had significantly lower platelet counts (126 × 10 9 /L vs. 164 × 10 9 /L, p = 0.01) and lower PA in response to ADP ( p < 0.05), collagen ( p < 0.05), and thrombin ( p = 0.06). Importantly, the magnitude of decrease in PA (δ) from presentation to 24 hours was independently associated with development of VTE (adjusted odds ratios per 10 aggregation unit decrease: δ-ADP, 1.31 [ p = 0.03]; δ-collagen, 1.36 [ p = 0.01]; δ-thrombin, 1.41 [ p < 0.01]). CONCLUSION: Severely injured patients with decreasing ex vivo measures of PA despite resuscitation have an increased risk of developing VTE. This may have implications for predicting development of VTE and for studying platelet targeted chemoprophylaxis regimens. LEVEL OF EVIDENCE: Prognostic/Epidemiological; Level III.


Subject(s)
Venous Thromboembolism , Humans , Venous Thromboembolism/etiology , Venous Thromboembolism/prevention & control , Platelet Aggregation , Thrombin , Platelet Function Tests , Adenosine Diphosphate
13.
Org Biomol Chem ; 20(30): 5958-5966, 2022 08 03.
Article in English | MEDLINE | ID: mdl-34935024

ABSTRACT

Lipids fulfill a variety of important physiological functions, such as energy storage, providing a hydrophobic barrier, and signal transduction. Despite this plethora of biological roles, lipids are rarely considered a potential target for medical applications. Here, we report a set of neutral small molecules that contain boronic acid and urea functionalities to selectively recognize the bacterial lipid phosphatidylglycerol (PG). The affinity and selectivity was determined using 1H NMR titrations and a liposome-based Alizarin Red S assay. Minimum inhibitory concentrations (MIC) were determined to assess antibacterial activity. The most potent compounds display an association constant with PG in liposomes of at least 5 × 103 M-1, function as antibacterial agents against Gram-positive bacteria (MIC = 12.5-25 µM), and show little hemolytic activity. Mode of action studies suggest that the boronic acids bind to the headgroup of the PG lipids, which leads to a change in membrane fluidity and ultimately causes membrane depolarization and cell death.


Subject(s)
Anti-Bacterial Agents , Phosphatidylglycerols , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Gram-Positive Bacteria , Liposomes/chemistry , Microbial Sensitivity Tests
14.
Nutr Metab Cardiovasc Dis ; 31(12): 3322-3325, 2021 11 29.
Article in English | MEDLINE | ID: mdl-34627691

ABSTRACT

BACKGROUND AND AIMS: Obesity is an independent risk factor for atherosclerotic cardiovascular disease (CVD), and platelet hyperactivation in obesity may contribute to this association. Olive oil consumption is associated with lower cardiovascular disease (CVD) risk in the general population. However, little is known for individuals with obesity. We investigated whether olive oil intake is associated with platelet activation in obesity. METHODS AND RESULTS: We assessed platelet activation (surface P-selectin expression) with and without thrombin exposure and diet composition in 63 patients with severe obesity. Among 63 subjects with obesity, the mean age was 32.2 ± 8.0 years and BMI 44.1 ± 8.5 kg/m2. Olive oil intake was stratified into <1 time/week (n = 21), 1-3 times/week (n = 18), ≥4 times/week (n = 24). Strata did not differ by age, BMI or platelet count. Unstimulated P-selectin expression did not differ by olive oil consumption. Subjects with more frequent olive oil intake exhibited lower P-selectin expression on submaximal thrombin exposure. CONCLUSIONS: More frequent olive oil intake is associated with reduced thrombin-induced platelet activation in obesity.


Subject(s)
Obesity , Olive Oil , Platelet Activation , Adult , Humans , Obesity/physiopathology , Olive Oil/administration & dosage , Platelet Activation/physiology
15.
Sci Adv ; 7(37): eabh2434, 2021 Sep 10.
Article in English | MEDLINE | ID: mdl-34516880

ABSTRACT

Given the evidence for a hyperactive platelet phenotype in COVID-19, we investigated effector cell properties of COVID-19 platelets on endothelial cells (ECs). Integration of EC and platelet RNA sequencing revealed that platelet-released factors in COVID-19 promote an inflammatory hypercoagulable endotheliopathy. We identified S100A8 and S100A9 as transcripts enriched in COVID-19 platelets and were induced by megakaryocyte infection with SARS-CoV-2. Consistent with increased gene expression, the heterodimer protein product of S100A8/A9, myeloid-related protein (MRP) 8/14, was released to a greater extent by platelets from COVID-19 patients relative to controls. We demonstrate that platelet-derived MRP8/14 activates ECs, promotes an inflammatory hypercoagulable phenotype, and is a significant contributor to poor clinical outcomes in COVID-19 patients. Last, we present evidence that targeting platelet P2Y12 represents a promising candidate to reduce proinflammatory platelet-endothelial interactions. Together, these findings demonstrate a previously unappreciated role for platelets and their activation-induced endotheliopathy in COVID-19.

18.
Lupus Sci Med ; 8(1)2021 03.
Article in English | MEDLINE | ID: mdl-33737451

ABSTRACT

OBJECTIVE: Hydroxychloroquine (HCQ) is a mainstay of therapy in the treatment of SLE. The effect of HCQ on platelets and vascular health is uncertain. We investigated the relationship between HCQ use and dose with platelet activity, platelet transcriptomics and vascular health in patients with SLE. METHODS: Platelet aggregation, platelet mRNA expression and vascular health (sublingual capillary perfused boundary region (PBR), red blood cell filling (RBCF) and brachial artery reactivity testing) were analysed by HCQ use and dose. RESULTS: Among 132 subjects with SLE (age: 39.7±12.9 years, 97% female), 108 were on HCQ. SLE disease activity was similar between subjects on and off HCQ. Platelet aggregation in response to multiple agonists was significantly lower in patients on HCQ. There were inverse relationships between HCQ dose and gene expression pathways of platelet activity. Gene expression of P-selectin (SELP) was inversely correlated with HCQ dose (r=-0.41, p=0.003), which was validated at the protein level. Subjects on HCQ had improved vascular function correlating with HCQ dose as measured by lower PBR (r=-0.52, p=0.007), higher RBCF (r=0.55, p=0.004) and greater brachial artery reactivity (r=0.43, p=0.056). CONCLUSION: HCQ use was associated with decreased platelet activation and activation-related transcripts and improved vascular health in SLE.


Subject(s)
Lupus Erythematosus, Systemic , Adult , Antirheumatic Agents/therapeutic use , Blood Platelets , Female , Humans , Hydroxychloroquine/therapeutic use , Lupus Erythematosus, Systemic/drug therapy , Male , Middle Aged
19.
Biomolecules ; 10(6)2020 06 03.
Article in English | MEDLINE | ID: mdl-32503152

ABSTRACT

A longstanding challenge is to understand how ribosomes parse mRNA open reading frames (ORFs). Significantly, GCN codons are over-represented in the initial codons of ORFs of prokaryote and eukaryote mRNAs. We describe a ribosome rRNA-protein surface that interacts with an mRNA GCN codon when next in line for the ribosome A-site. The interaction surface is comprised of the edges of two stacked rRNA bases: the Watson-Crick edge of 16S/18S rRNA C1054 and the adjacent Hoogsteen edge of A1196 (Escherichia coli 16S rRNA numbering). Also part of the interaction surface, the planar guanidinium group of a conserved Arginine (R146 of yeast ribosomal protein Rps3) is stacked adjacent to A1196. On its other side, the interaction surface is anchored to the ribosome A-site through base stacking of C1054 with the wobble anticodon base of the A-site tRNA. Using molecular dynamics simulations of a 495-residue subsystem of translocating ribosomes, we observed base pairing of C1054 to nucleotide G at position 1 of the next-in-line codon, consistent with previous cryo-EM observations, and hydrogen bonding of A1196 and R146 to C at position 2. Hydrogen bonding to both of these codon positions is significantly weakened when C at position 2 is changed to G, A or U. These sequence-sensitive mRNA-ribosome interactions at the C1054-A1196-R146 (CAR) surface potentially contribute to the GCN-mediated regulation of protein translation.


Subject(s)
RNA, Messenger/chemistry , Ribosomes/chemistry , Molecular Dynamics Simulation , Surface Properties
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